Prince Charles said today that he is "thrilled" at the prospect of becoming a grandfather.

"I'm thrilled, marvelous," Prince Charles said today. "It's a very nice thought of grandfatherhood in my old age, if I may say so, so that's splendid."

Kate Middleton left King Edward VII Hospital in London this morning after being admitted four days ago following the palace's announcement that she is pregnant and was being treated for hyperemesis gravidarum.

When initially approached by reporters, the prince joked, "How do you know I'm not a radio station?"

He was referring to an Australian radio station's prank call to the hospital on Tuesday where two disc jockeys pretended to be Queen Elizabeth II and Prince Charles looking to speak to Kate.

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"The Duchess of Cambridge has been discharged from the King Edward VII Hospital and will now head to Kensington Palace for a period of rest," Nick Loughran, the assistant press secretary to the Duke and Duchess of Cambridge, said in a statement. "Their Royal Highnesses would like to thank the staff at the hospital for the care and treatment The Duchess has received."

Middleton, 30, who is less than 12 weeks pregnant, left the hospital with Prince William at 11 a.m. GT today. A smiling Middleton was holding yellow flowers and waved to the crowd as she departed from the hospital in a black car.

The Duke and Duchess were spending time with her parents in Bucklebury when she became ill with the symptoms of hyperemesis gravidarum, or acute nausea.

Prince William sprung into action and drove his wife, along with their personal security team, 50 miles in their Range Rover to the hospital, where Kate was placed on an IV drip.

The royal family was only notified of Kate's pregnancy a few hours before the rest of the world.

The royal couple decided to go public with the pregnancy because Middleton had to be hospitalized Monday afternoon, a palace source said.

Hyperemesis gravidarum, or acute nausea, is usually diagnosed about nine weeks into a pregnancy, and in most cases resolves itself by 16 or 20 weeks, according to Dr. Ashley Roman, a professor and obstetrician-gynecologist at NYU Langone Medical Center.